Adaptive Release of Content provides controls to release content to users based on a set of rules provided by the course author. The rules may be related to availability, date and time, individual users and user groups (such as course Groups), scores or attempts on any Gradebook item, or review status of another item in the course. To give an analogy, adaptive release is like those old Goosebumps books where the outcome changes depending on the reader's decisions along the way.
BrainHoney, in their latest release (Dec 2010), has added support for adaptive release. Teachers now have the ability to:

Allow students to view a particular unit or resource only after they have attained a minimum score on a quiz.

Share different materials and resources with students in different sections of the same course.

Restrict students from taking a test until they have reviewed relevant course materials.

Make the next assignment available only to those who have read specific material.